The present invention relates to a multiprocessor data processing system in which processes can be intercommunicated among a plurality of processors and the intercommunication of processes can be effected in a firmware manner.
With multi-processor data processing systems known in the art, to effect intercommunication of processes among a plurality of processors (a process in which when one processor has executed a program of a certain magnitude, the remaining processing is taken over and executed by another processor), under control of an operating system (OS), a main memory unit which is provided common to all the processors stores the necessary information for intercommunication applied from any processor and the information is read out by another processor.
In accordance with this type of intercommunication of processes, as for example, in the case of an electronic switching system of the stored program control (SPC) type, when one processor performs a process of receiving a request for connection from a calling party and reading and storing the information relating to the calling party and the destination in the main memory unit, another processor takes over the rest of the work and connects the circuit between the calling party and the destination.
A disadvantage of this prior art method is that the intercommunication of processes requires accesses to the main memory unit and this interferes with accesses of other processors to the main memory unit which are necessary for the execution of processes by the other processors. Consequently, there results a reduction in the processing capacity of the multi-processor system on the whole.